Heinbich large



March 8, 1932. H.- LANGE 1,848,730

WELL FILTER Filed Nov. 1. 1930 Patented Mar. 8, 1932- PATENT OFFICE HEINRICH LARGE, 0]? ALTONA-EIDELSTEDT, GERMANY WELL FILTER Application filed November 1, 1930, Serial No. 492,761, and. in Germany June 28, 1928.

This invention relates to a well filter adapted to be employed entirely without fabric. Filters, which extend into the water supplying strata of well plants and the like and con- 5' sist of a pipe provided with slots, closed by a bottom plate, are already known. The bars of these filters form a ring corresponding to the diameter of the suction pipe belonging thereto, and they are connected together in such a manner that a ring or head projects either inwardly or outwardly. These beads are provided with grooves, by which the bars are held. The distance between the bars cannot naturally vary considerably, so that a filter cannot be employed for a certain grain of sand, if no fabric is wrapped around same. The woven fabric however becomes clogged with sand very easily, as has been found in practice, and. consequently has only a short life, which is further reduced chiefly by the destructive properties of the diflerent qualities of the water.

It may be said briefly therefore, that filter" pipes with internal and external projections are dilficult to fit and remove or to clean. The woven fabricis open to the objection that, when being let into the well, the fabric easily becomes damaged and its durability is limited. The above mentioned filters, the bars of which are held by rings, grooves or the like, are not made so that the distance between the bars is uniform, and consequently it is absolutely necessary to employ a fabric with the result that both disadvantages are present.

The present invention relates to a well filter, which completely overcomes the objections of the known filter. The filter pipe for this purpose, consists in known manner of concentrically arranged bars. the connecting means between the individual bars being arranged so that it does not project outwardly or inwardly. The connecting means is pref-- erably a welding and may also be carried out in some other manner, for example by means of wires connecting the individual bars. In the latter instance a spacer is inserted between the bars for keeping same at a uniform distance apart. The production of a welded filter tube is effected for example by binding the bars on the pipe or the like in a suitable manner and then welding same, the distance between the individual bars being kept uniform by spacers. For obtaining a uniform distance between the bars portions of the supporting pipe may be milled out. Two spirals arranged concentrically the one within the other are also employed for producing a filter pipe. In this instance spacing plates are employed 'for obtaining the required distance apart.

According to the invention a filter pipe is produced, which is smooth on the inner and on the outer side and for the fitting of which no gravel filling or packing is required.' The filter pipe is made according to the actual grain of the sand. The fitting of same at great depth is easily possible on account of what has already been said. 'The making of any desired sizes presents no difliculties, and the filter pipe is absolutely reliable and has a long life.

An embodiment of the invention is illusing drawings in which:

Fig. 1 shows a finished filter pipe according to the invention.

Fig. 2 is a cross section of Fig. 1.

Fig. 3 shows in longitudinal section a filter with internal and external spirals for the purpose of production.

The filter consists of separate bars a, which are arranged at distances 1) apart. The bars a may be of any desired cross section and are arranged in a circle, so that they form the suction cross section of the corresponding pipe. The connecting means, especially the welding c, is located entirely within the pipe wall sothat it does not project therefrom on the inner side or on the outer side. The filter has a bottom plate 6, which at the same time guides the filter bars. The connection pipe d is fitted on the upper end of the filter in known manner.

Fig. 3 shows external and internal spirals f and f which serve for holding the bars of the filter. Gauges or spacing plates may be placed between the bars so that the distance between the bars is uniform and an existing grain of sand is determined for a filter pipe.

I claim A well filter, comprising inrcombination, a pipe with smooth inner and outer wall surfaces formed of separate bars arranged in the longitudinal direction of the filter pipe, and means such as welding for connecting said separate concentrically arranged bars situated within the wall of said pipe formed by said bars.

In testimony whereof I affix my signature.

HEINRICH LANGE. 

